Device, system and method for on-line explosive deslagging

ABSTRACT

A device, system and method permitting on-line explosives-based cleaning and deslagging of a fuel burning facility ( 31 ) such as a boiler, furnace, incinerator, or scrubber. A coolant, such as ordinary water, is delivered to the explosives ( 101 ) to prevent them from detonating due to the heat of the on-line facility. Thus, controlled, appropriately-timed detonation can be initiated as desired, and boiler scale and slag is removed without the need to shut down or cool down the facility.

FIELD OF THE INVENTION

This disclosure relates generally to the field of boiler/furnacedeslagging, and particularly, discloses a device, system and methodallowing on-line, explosives-based deslagging.

BACKGROUND OF THE INVENTION

A variety of devices and methods are used to clean slag and similardeposits from boilers, furnaces, and similar heat exchange devices. Someof these rely on chemicals or fluids that interact with and erodedeposits. Water cannons, steam cleaners, pressurized air, and similarapproaches are also used. Some approaches also make use of temperaturevariations. And, of course, various types of explosive, creating strongshock waves to blast slag deposits off of the boiler, are also verycommonly used for deslagging.

The use of explosive devices for deslagging is a particularly effectivemethod, as the large shock wave from an explosion, appropriatelypositioned and timed, can easily and quickly separate large quantitiesof slag from the boiler surfaces. But the process is costly, since theboiler must be shut down (i.e. brought off line) in order to performthis type of cleaning, and valuable production time is thereby lost.This lost time is not only the time during which the cleaning process isbeing performed. Also lost are several hours prior to cleaning when theboiler must be taken off line to cool down, and several hours subsequentto cleaning for the boiler to be restarted and brought into fulloperational capacity.

Were the boiler to remain on-line during cleaning, the immense heat ofthe boiler would prematurely detonate any explosive placed into theboiler, before the explosive has been properly positioned fordetonation, rendering the process ineffective and possibly damaging theboiler. Worse, loss of control over the precise timing of detonationwould create a serious danger for personnel located near the boiler atthe time of detonation. So, to date, it has been necessary to shut downany heat exchange device for which explosives-based deslagging isdesired.

Several U.S. patents have been issued on various uses of explosives fordeslagging. U.S. Pat. Nos. 5,307,743 and 5,196,648 disclose,respectively, an apparatus and method for deslagging wherein theexplosive is placed into a series of hollow, flexible tubes, anddetonated in a timed sequence. The geometric configuration of theexplosive placement, and the timing, are chosen to optimize thedeslagging process.

U.S. Pat. No. 5,211,135 discloses a plurality of loop clusters ofdetonating cord placed about boiler tubing panels. These are againgeometrically positioned, and detonated with certain timed delays, tooptimize effectiveness.

U.S. Pat. No. 5,056,587 similarly discloses placement of explosive coraabout the tubing panels at preselected, appropriately spaced locations,and detonation at preselected intervals, once again, to optimize thevibratory pattern of the tubing for slag separation.

Each of these patents discloses certain geometric configurations forplacement of the explosive, as well as timed, sequential detonation, soas to enhance the deslagging process. But in all of these disclosures,the essential problem remains. If the boiler were to remain on-lineduring deslagging, the heat of the boiler would cause the explosive toprematurely detonate before it is properly placed, and this uncontrolledexplosion will not be effective, may damage the boiler, and could causeserious injury to personnel.

U.S. Pat. No. 2,840,365 appears to disclose a method for introducing atube into “a hot space such as an oven or a slag pocket for an oven”prior to the formation of deposits in the hot space; continuouslyfeeding a coolant through the tube during the formation of deposits inthe hot space, and, when it is time to break the deposits, inserting anexplosive into the tube after the formation of the deposits while thetube is still somewhat cooled, and detonating the explosive before ithas a chance to heat up and undesirably self-detonate. (See, e.g., col.1, lines 44-51, and claim 1) There are a number of problems with theinvention disclosed by this patent.

First, the hot space according to this patent must be thoroughlyprepared and preconfigured, in advance, for the application of thismethod, and the tubes that contain the coolant and later the explosive,as well as the coolant feeding and discharge system, must be in place ona more or less permanent basis. The tubes are “inserted before thedeposits begin to form or before they are formed sufficiently to coverthe points where one wishes to insert the tubes” and are “cooled by thepassage of a cooling fluid . . . therethrough during operation.” (col.2, lines 26-29 and col. 1, lines 44-51) It is necessary “to providesealable holes in several bricks for allowing the tube . . . to beinserted, or . . . to remove the bricks during operation of the furnaceso that a hole is formed through which the tube may be inserted.” (col.2, lines 32-36) The tubes are supported “at the back end of the pocketupon supports made for the purpose, e.g., by a stepped shape of the backof the wall . . . [or] at the front end or in front of and in the wall .. . [or by having] at least the higher tubes . . . rest immediately uponthe deposits already formed.” (col. 2, lines 49-55) A complicated seriesof hoses and ducts are attached for “feeding cooling water . . . anddischarging said cooling water.” (col. 3, lines 1-10, and FIG. 2generally) And, the tubes must be cooled whenever the hot space is inoperation to prevent the tubes from burning and the water from boiling.(see, e.g., col. 3 lines 14-16 and col. 1, lines 44-51) In sum, thisinvention cannot simply be brought onto the site of a hot space afterdeposits have formed and then used at will to detonate the depositswhile the hot space is still hot. Rather, the tubes must be in place andcontinuously cooled essentially throughout the entire operation of thehot space and the accumulation of deposits. And, significantaccommodations and preparation such as tube openings and supports, thetubes themselves, and coolant supply and drainage infrastructure, mustbe permanently established for the associated hot space.

Second, the method disclosed by this patent is dangerous, and must beperformed quickly to avoid danger. When the time arrives to break theslag deposits, “the pipes . . . are drained,” various cocks, hoses,bolts and an inner pipe are loosened and removed, and “explosive chargesare now inserted [into the pipe] . . . immediately after termination ofthe cooling so that no danger of self-detonation exists, because theexplosive charges cannot become too hot before being explodedintentionally.” (col. 3, lines 17-28) Then, the “tubes are explodedimmediately after stopping the cooling at the end of the operation ofthe furnace. . . . ” (col. 1, lines 49-51) Not only is the process ofdraining the pipe and readying it to receive the explosive fairlycumbersome, it must also be done in a hurry to avoid the danger ofpremature explosion. As soon as the coolant flow is ceased, time is ofthe essence, since the tubes will begin to heat up, and the explosivesmust be placed into the tubes and purposefully detonated quickly, beforethe heating of the tube become so great that the explosive accidentallyself-detonates. There is nothing in this patent that discloses orsuggests how to ensure that the explosive will not self-detonate, sothat the process does not have to be unnecessarily hurried to avoidpremature detonation.

Third, the pre-placement of the tubes as discussed above constrains theplacement of the explosive when the time for detonation arrives. Theexplosives must be placed into the tubes in their preexisting location.There is no way to simply approach the hot space after the slagaccumulation, freely choose any desired location within the hot spacefor detonation, move an explosive to that location in an unhurriedmanner, and then freely and safely detonate the explosive at will.

Fourth, it may be inferred from the description that there is at leastsome period of time during which the hot space must be taken out ofoperation. Certainly, operation must cease long enough for the site tobe prepared and fitted to properly utilize the invention as describedearlier. Since one object of the invention is to “prevent the oven . . .to be taken out of operation for too long a time,” (col. 1, lines 39-41,emphasis added), and, since the “tubes are exploded immediately afterstopping the cooling at the end of the operation of the furnace or thelike” (col. 1, lines 49-51, emphasis added), it appears from thisdescription that the hot space is in fact shut down for at least sometime prior to detonation, and that the crux of the invention is tohasten the cooling of the slag body after shutdown so that detonationcan proceed more quickly without waiting for the slag body to cool downnaturally (see col. 1, lines 33-36), rather than to allow detonation tooccur while the hot space is in full operation without any shutdown atall.

Finally, because of all the site preparation that is needed prior tousing this invention. and due to the configuration shown and describedfor placing the tubes, this invention does not appear to be usableacross the board with any form of hot space device, but only with alimited type of hot space device that can be readily preconfigured tosupport the disclosed horizontal tubing structure as disclosed.

Luxembourg patent no. 1,977 has similar problems to U.S. Pat. No.2,840,365, particularly: insofar as this patent also requires asignificant amount of site preparation and preconfiguration before theinvention disclosed thereby can be used; insofar as one cannot simplyapproach the hot space after the slag accumulation, freely choose anydesired location within the hot space for detonation, move an explosiveto that location in an unhurried manner, and then freely and safelydetonate the explosive at will; and insofar as the types of hot spacedevices to which this patent applies also appear to be limited.

According to the invention disclosed by this patent, a “blasting hole”must be created within the subject hot space before the invention can beused. (translation of page 2, second full paragraph) Such holes are“drilled at the time of need or made prior to the formation of the solidmass.” (translation of paragraph beginning on page 1 and ending on page2) Since the device for implementing the process of the invention“includes at least a tube that permits feeding the cooling fluid intothe bottom of the blasting hole” (translation of page 2, fourth fullparagraph) and, in one form of implementation, “a retaining plate . . .positioned at the bottom of the blast hole (translation of paragraphbeginning on page 2 and ending on page 3), and since it is a key featureof the invention that the blast hole is filled with coolant prior to andduring the insertion of the explosive, it may be inferred from thisdescription that the blast hole is substantially vertical in itorientation, or at least has a significant enough vertical component toenable water to effectively accumulate and pool within the blast hole.

Because the subject hot space must be preconfigured with a blast hole orholes (with implicitly at least a substantial vertical component) beforethis invention can be used, it is again not possible to simply approachan unprepared hot space at will after deposits have accumulated, anddetonate at will. Since the coolant and the explosive must be containedwithin the blast holes, it is not possible to freely move and positionthe explosive wherever desired within the hot space. The explosives canonly be positioned and detonated within the blast holes pre-drilled forthat purpose. Due to the at least partially vertical orientation of theblast holes, the angle of approach for introducing the coolant and theexplosive is necessarily constrained. Also, while it is not clear fromthe disclosure how the blast holes are initially drilled, it appearsthat at least some amount of boiler shutdown and/or disruption would berequired to introduce these blast holes.

Finally, in both of these cited patents, the components which hold thecoolant (the tubes for U.S. Pat. No. 2,840,365 and the blast holes forLU 41,977) reside within the hot space. and are already very hot whenthe time arrives to deslag. The object of both of these patents, is tocool these components down before the explosive is introduced. U.S. Pat.No. 2,840,365 achieves this by virtue of the fact that the tubes arecontinuously cooled throughout the operation of the hot space, which,again, is very disruptive and requires significant preparation of andmodification to the hot space. And LU 41,977 clearly states that”[a]ccording to all its forms of implementation, the device is put inplace without a charge for the purpose of cooling the blast hole for afew hours with the injection fluid. (translation of page 4, last fullparagraph, emphasis added) It would be desirable to avoid this cooldownperiod altogether and therefor save time in the deslagging process, andto simply introduce a cooled explosive into a hot space at will withoutany need to alter or preconfigure the boiler, and to then detonate thecooled explosive at will once it has been properly placed in whateverdetonation location is desired. And most certainly, the application ofLU 41,977 is limited only to hot spaces into which it is feasible tointroduce a blast hole, which appears to eliminate many types ofheat-exchange device into which it is not feasible to introduce a blasthole.

It would be desirable if a device, system and method could be devisedwhich would allow explosives to safely and controllably be used fordeslagging, on-line, without any need to shut down the boiler during thedeslagging process. By enabling a boiler or similar heat-exchange deviceto remain on-line for explosives-based deslagging, valuable operationstime for fuel-burning facilities could then be recovered.

It is therefore desired to provide a device, system and method wherebyexplosives may be used to clean a boiler, furnace, scrubber, or anyother heat exchange device, fuel burning, or incinerating device,without requiring that device to be shut down, thereby enabling thatdevice to remain in full operation during deslagging.

It is desired to enable valuable operations time to be recovered, byvirtue of eliminating the need for shutdown of the device or facility tobe cleaned.

It is desired to enhance personnel safety and facility integrity, byenabling this on-line explosives-based cleaning to occur in a safe andcontrolled manner.

SUMMARY OF THE INVENTION

This invention enables explosives to be used for cleaning slag from ahot, on-line boiler, furnace, or similar fuel-burning or incinerationdevice, by delivering a coolant to the explosive which maintains thetemperature of the explosive well below what is required for detonation.The explosive, while it is being cooled, is delivered to its desiredposition inside the hot boiler without detonation. It is then detonatedin a controlled manner, at the time desired.

While many obvious variations may occur to someone of ordinary skill inthe relevant arts, the preferred embodiment disclosed herein uses aperforated or semi-permeable membrane which envelopes the explosive andthe cap or similar device used to detonate the explosive. A liquidcoolant, such as ordinary water, is delivered at a fairly constant flowrate into the interior of the envelope, thereby cooling the externalsurface of the explosive and maintaining the explosive well belowdetonation temperature. Coolant within the membrane in turn flows out ofthe membrane at a fairly constant rate, through perforations ormicroscopic apertures in the membrane. Thus cooler coolant constantlyflows into the membrane while hotter coolant that has been heated by theboiler flows out of the membrane, and the explosive is maintained at atemperature well below that needed for detonation. Coolant flow ratestypical of the preferred embodiment run between 20 and 80 gallons perminute.

This coolant flow is initiated as the explosive is first being placedinto the hot boiler. Once the explosive has been moved into the properposition and its temperature maintained at a low level, the explosive isdetonated as desired, thereby separating the slag from, and thuscleaning, the boiler.

BRIEF DESCRIPTION OF THE DRAWING

The features of the invention believed to be novel are set forth in theappended claims. The invention, however, together with further objectsand advantages thereof, may best be understood by reference to thefollowing description taken in conjunction with the accompanyingdrawing(s) in which:

FIG. 1 depicts the preferred embodiment of a device, system and methodused to perform on-line cleaning of a fuel-burning facility.

FIG. 2 depicts the device in its disassembled (preassembly) state, andis used to illustrate the method by which this device is assembled foruse.

FIG. 3 illustrates the use of the assembled cleaning device to clean anon-line fuel burning or incineration facility.

FIG. 4 depicts an alternative preferred embodiment of this invention,which reduces coolant weight and enhances control over coolant flow, andwhich utilizes remote detonation.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 depicts the basic tool used for on-line cleaning of afuel-burning facility such as a boiler, furnace, or similar heatexchange device, or an incineration device, and the discussion followingoutlines the associated method for such on-line cleaning.

The cleaning of the fuel burning and/or incineration facility is carriedout in the usual manner by means of an explosive device 101, such as butnot limited to an explosive stick or other explosive device orconfiguration, placed appropriately inside the facility, and thendetonated such that the shock waves from the explosion will cause slagand similar deposits to dislodge from the walls, tubing, etc. of thefacility. This explosive device 101 is detonated by a standard explosivecap 102 or similar detonating device, which causes controlled detonationat the desired instant, based on a signal sent from a standard initiator103, by a qualified operator.

However, to enable explosives-based cleaning to be performed on-line,i.e., with any need to power down or cool down the facility, two priorart problms must be overcome. First, since explosives areheat-sensitive, the placement of an explosive into a hot furnace cancause premature, uncontrolled detonation, creating danger to both thefacility and personnel around the explosion. Hence, it is necessary tofind a way of cooling the explosive while it is being placed in theon-line facility and readied for detonation. Second, it is not possiblefor a person to physically enter the furnace or boiler to place theexplosive, due the immense heat of the on-line facility. Hence, it isnecessary to devise a means of placing the explosive that can be managedand controlled from outside the burner or furnace.

In order to properly cool the explosive, a cooling envelope 104 isprovided which completely envelopes the explosive. During operation,this envelope will have pumped into it a coolant, such as ordinarywater, that will maintain the explosive device 101 in a cooled-downstate until it is ready for detonation. Because of the direct contactbetween the coolant and the explosive device 101, this device is ideallymade of a plastic or similar waterproof housing that contains the actualexplosive powder or other explosive material.

This cooling envelope 104 is a semi-permeable membrane that allows waterto flow out of it at a fairly controlled rate. It can have a series ofsmall perforations punched into it, or can be constructed of anysemi-permeable membrane material appropriate to its coolant-deliveryfunction as will outlined herein. This semi-permeability characteristicis illustrated by the series of small dots 105 scattered throughout theenvelope 104 as depicted in FIG. 1.

At an open end (coolant entry opening), the envelope 104 is attached toa coolant delivery pipe 106 via an envelope connector 107. As depictedhere, the envelope connector 107 is cone-shaped apparatus permanentlyaffixed to the coolant delivery pipe 106, and it further comprises astandard threading 108. The envelope itself, at this open end, is fittedand permanently affixed to complementary threading (not shown) that iseasily screwed into and fitted with the threading 108 of the connector107. While FIG. 1 depicts screw threads in connection with a cone-shapedapparatus as the particular means of attaching the envelope 104 to thecoolant delivery pipe 106, any type of clamp, and indeed, many othermeans of attachment know to someone of ordinary skill would also beprovide a feasible and obvious alternative, and such substitutions forattaching the envelope 104 to the pipe 106 are fully contemplated to bewithin the scope of this disclosure and its associated claims.

The coolant delivery pipe 106, in the region where said pipe resideswithin the envelope 104, further contains a number of coolant deliveryapertures 109, twin ring holders 110, and an optional butt plate 111.The explosive device 101 with cap 102 is affixed to one end of anexposive connector (broomstick) 112 with explosive-to-broomstickattachment means 113 such as duct tape, wire, rope, or any other meansthat provides a secure attachment. The other end of the broomstick isslid through the twin ring holders 110 until it abuts the butt plate111, as shown. At that point, the broomstick, optionally, may be furthersecured by means of, for example, a bolt 114 and wingnut 115 runningthrough both the broomstick 112 and the pipe 106 as depicted. While therings 110, butt plate 111, and nut and bolt 115 and 114 provide one wayto secure the broomstick 112 to the pipe 106, many other ways to securethe broomstick 112 to the pipe 106 can also be devised by someone ofordinary skill, all of which are contemplated within the scope of thisdisclosure and its related claims. The length of the broomstick 112 mayvary, though for optimum effectiveness, it should maintain the explosive101 at approximately two or more feet from the end of the pipe 106 thatcontains the coolant delivery apertures 109, which, since it isdesirable to reuse the pipe 106 and its components, will minimize anypossible damage to the pipe 106 and said components when the explosiveis detonated, and will also reduce any shock waves sent back down thepipe to the operator of this invention.

With the configuration disclosed thus far, a coolant such as water underpressure entering the left side of the pipe 106 as depicted in FIG. 1will travel through the pipe and exit the pipe through the coolantdelivery apertures 109 in a manner illustrated by the directional flowarrows 116. Upon exiting the pipe 106 through the apertures 109, thecoolant then enters the inside of the envelope 104 and begins to fill upand expand the envelope. As the coolant fills the envelope, it will comeinto contact with and cool the explosive device 101. Because theenvelope 104 is semi-permeable (105), water will also exit the envelopeas the envelope becomes full as shown by the directional arrows 116 a,and so the entry under pressure of new water into the pipe 106 combinedwith the exit of water through the semipermeable (105) envelope 104,will deliver a continuous and stable flow of coolant to the explosivedevice 101.

The entire cooling and cleaning delivery assembly 11 disclosed thus far,is in turn connected to a coolant supply and explosive positioningsystem 12 as follows. A hose 121 with water service (for example, butnot limited to, a standard 3/4″ Chicago firehose and water service) isattached to a hydraulic tube 122 (e.g. pipe) using any suitable hoseattachment fitting 123. The coolant, preferable ordinary water, runsunder pressure through the hose as indicated by the directional flowarrow 120. The end of the tube 122 opposite the hose 121 containsattachment means 124 such as screw threading, which complements andjoins with similar threading 117 on the pipe 106. Of course, any meansknown to someone of ordinary skill for joining the tube 122 and pipe 106in the manner suggested by the arrow 125 in FIG. 1, such that coolantcan run from the hose 121 through the tube 122, into the pipe 106, andfinally into the envelope 104, is acceptable and contemplated by thisdisclosure and its associated claims.

Finally, detonation is achieved by electrically connecting the explosivecap 102 to the initiator 103. This is achieved by connecting theinitiator 103 to a lead wire pair 126, in turn connecting to a secondlead wire pair 118, in turn connecting to a cap wire pair 119. This capwire pair 119 is finally connected to the cap 102. The lead wire pair126 enters the tube 122 from the initiator 103 through a lead wire entryport 127 as shown, and then runs through the inside of the tube 122, andout the far end of the tube. (This entry port 127 can be constructed inany manner obvious to someone of ordinary skill, so long as it enablesthe wire 126 to enter the tube 122 and averts any significant coolantleakage.) The second lead wire pair 118 runs through the inside of thepipe 106, and the cap wire pair 119 is enclosed within the envelope 104as shown. Thus, when the initiator 103 is activated by the operator, anelectrical current flows straight to the cap 102, detonating theexplosive 101.

While FIG. 1 thus depicts electronic detonation of the cap and explosivevia a hard wire signal connection, it is contemplated that anyalternative means of detonation known to someone of ordinary skill couldalso be employed, and is encompassed by this disclosure and itsassociated claims. Thus, for example, detonation by a remote controlsignal connection between the initiator and cap (which will be furtherdiscussed in FIG. 4), eliminating the need for the wires 126, 118, and119, is very much an alternative preferred embodiment for detonation.Similarly, non-electronic shock (i.e. percussion), and heat-sensitivedetonation can also be used within the spirit and scope of thisdisclosure and its associated claims.

While any suitable liquid can be pumped into this system as a coolant,the preferred coolant is ordinary water. This is less expensive than anyother coolant, it performs the necessary cooling properly, and it isreadily available at any site which has a pressurized water supply thatmay be delivered into this system. Notwithstanding this preference forordinary water as the coolant, this disclosure contemplates that manyother coolants known to someone of ordinary skill can also be used forthis purpose as well, and all such coolants are regarded to be withinthe scope of the claims.

At this point, we turn to discuss methods by which the on-line cleaningdevice disclosed above is assembled for use and then used. FIG. 2 showsthe preferred embodiment of FIG. 1 in preassembly state, disassembledinto its primary components. The explosive 101 is attached to the cap102, with the cap in turn connected to the one end of the cap wire pair119. This assembly is attached to one end of the broomstick 112 usingthe explosive-to-broomstick attachment means 113 such as duct tape,wire, rope, etc., or any other approach known to someone of ordinaryskill, as earlier depicted in FIG. 1. The other end of the broomstick112 is slid into the twin ring holders 110 of the pipe 106 until itabuts the butt plate 111, also as earlier shown in FIG. 1. The bolt 114and nut 115, or any other obvious means, may be used to further securethe broomstick 112 to the pipe 106. The second lead wire pair 118 isattached to the remaining end of the cap wire pair 119 to provide anelectrical connection therebetween. Once this assemblage has beenachieved, the semipermeable (105) cooling envelope 104 is slid over theentire assembly, and attached to the envelope connector 107 using thethreading 108, clamp, or any other obvious attachment means, as depictedin FIG. 1.

The right-hand side (in FIG. 2) of lead wire pair 126 is attached to theremaining end of the second lead wire pair 118 providing an electricalconnection therebetween. The pipe 106 is then attached to one end of thehydraulic tube 122 as also discussed in connection with FIG. 1, and thehose 121 is hooked to the other end of the tube 122, completing allcoolant delivery connections. The initiator 103 is attached to theremaining end of the lead wire pair 126 forming an electrical connectiontherebetween, and completing the electrical connection from theinitiator 103 to the cap 102.

When all of the above connections have been achieved, the on-linecleaning device is fully assembled into the configuration shown in FIG.1.

FIG. 3 now depicts the usage of this fully assembled on-line cleaningdevice, to clean a fuel burning facility 31 such as a boiler, furnace,scrubber, incinerator, etc., and indeed any fuel-burning orrefuse-burning device for which cleaning by explosives is suitable. Oncethe cleaning device has been assembled as discussed in connection withFIG. 2, the flow 120 of coolant through the hose 121 is commenced. Asthe coolant passes through the hydraulic tube 122 and pipe 106, it willemerge from the coolant apertures 109 to fill the envelope 104 andprovide a flow of coolant (e.g. water) to surround the explosive 101,maintaining the explosive at a relatively cool temperature. Optimal flowrates range between approximately and 80 gallons per minute.

Once this flow is established and the explosive is maintained in a coolstate, the entire cooling and cleaning delivery assembly 11 is placedinto the on-line facility 31 through an entry port 32 such as a manway,handway, portal, or other similar means of entry, while the coolantsupply and explosive positioning system 12 remains outside of saidfacility. At a location near where assembly 11 meets system 12, the pipe106 or tube 122 is rested against the bottom of the entry port 32 at thepoint designated by 33. Because the coolant pumped through the envelope104 introduces a fair amount of weight into assembly 11 (with someweight also added to the system 12), a downward force designated by 34is exerted to the system 12, with the point 33 acting as the fulcrum.Applying appropriate force 34 and using 33 as the fulcrum, the operatorpositions the explosive 101 to the position desired. It is furtherpossible to place a fulcrum fitting device (not shown) at location 33,so as to provide a stable fulcrum and also protect the bottom of theport 32 from the significant weight pressure that will be exerted at thefulcrum. Throughout this time, new (cooler) coolant is constantlyflowing into the system while older (hotter) coolant which has beenheated by the on-line facility exits via the semipermeable envelope 104,so that this continued flow of coolant into the system maintains theexplosive 101 in a cool state. Finally, when the operator has moved theexplosive 101 in the desired position, the initiator 103 is activated toinitiate the explosion. This explosion creates a shock wave in region35, which thereby cleans and deslags that region of the boiler orsimilar facility, while the boiler/facility is still hot and on-line.

Referring back to FIG. 2, during the explosion, the explosive 101, cap102, cap wire 119, broomstick 112, and broomstick attachment means 113are all destroyed by the explosion, as is the envelope 104. Thus, it ispreferable to fabricate the broomstick 112 out of wood or some othermaterial that is extremely inexpensive and disposable after a singleuse. Similarly, the envelope 104, which is for a single use only, shouldbe fabricated from a material that is inexpensive, yet durable enough tomaintain physical integrity while water is being pumped into it underpressure. And of course, this envelope 104 must be semipermeable (105),which can be achieved, for example, by using any appropriate membranewhich in essence acts as a filter, either with a limited number ofmacroscopic puncture holes, or a large number of fine, microscopicholes.

On the other hand, all other components, particularly the pipe 106 andall of its components 107, 108, 109, 110, 111, and 118, as well as thebolt 114 and nut 115, are reusable, and so should be designed frommaterials that provide proper durability in the vicinity of theexplosion. (Again, note that the length of the broomstick 112 determinesthe distance of the pipe 106 and its said components from the explosion,and that approximately two feet or more is a desirable distance toimpose between the explosive 101 and any said component of the pipe106.)

Additionally, because coolant filling the envelope 104 adds significantweight to the right of the fulcrum 33 in FIG. 3, the materials used toconstruct the cleaning delivery assembly 11 should be as lightweight aspossible so long as they can endure both the heat of the furnace and theexplosion (the envelope 104 should be as light as possible yet resistantto any possible heat damage), while to counterbalance the weight of 11,the coolant supply and explosive positioning system 12 may beconstructed of heavier materials, and may optionally include addedweight simply for ballast. Water weight can also be counterbalanced bylengthening the system 12 so that force 34 can be applied farther fromthe fulcrum 33. And of course, although the system 12 is shown here asembodying a single tube 122, it is obvious that this assembly can alsobe designed to employ a plurality of tubes attached to one another, andcan also be designed so as to telescope from a shorter tube into alonger tube. All such variations, and others that may be obvious tosomeone of ordinary skill, are fully contemplated by this disclosure andincluded within the scope of its associated claims.

FIG. 4 depicts an alternative preferred embodiment of this inventionwith reduced coolant weight and enhanced control over coolant flow, andremote detonation.

In this alternative embodiment, the cap 102 now detonates the explosive101 by a remote control, wireless signal connection 401 sent from theinitiator 103 to the cap 102. This eliminates the need for the lead wireentry port 127 that was shown in FIG. 1 on the tube 122, as well as theneed to run the wire pairs 126, 118 and 119 through the system to carrycurrent from the initiator 103 to the cap 102.

FIG. 4 further shows a modified envelope 104′, which is narrower wherethe coolant first enters from the pipe 106 and wider in the region 402of the explosive 101. Additionally, this envelope is impermeable in theregion where coolant first enters the pipe, and permeable (105) only inthe region near the explosive 101. This modification achieves tworesults.

First. since a main object of this invention is to cool the explosive101 so that it can be introduced into an on-line fuel-burning facility,it is desirable to make the region of the envelope 104′ where theexplosive is not present as narrow as possible, thus reducing the waterweight in this region and making it easier to achieve a proper weightbalance about the fulcrum, as discussed in connection with FIG. 3.Similarly, by broadening the envelope 104′ near the explosive 101, asshown by 402, a greater volume of coolant will reside in precisely thearea that it is needed to cool the explosive 101, thus enhancing coolingefficiency.

Second, since it desirable for hotter coolant that has been in theenvelope for a period of time to leave the system in favor of coolercoolant being newly introduced into the envelope, the impermeability ofthe entry region and midsection of the envelope 104′ will enable allnewly-introduced coolant to reach the explosive before that coolant isallowed to exit the envelope 104′ from its permeable (105) section 402.Similarly, the coolant in the permeable region of the envelope willtypically have been in the envelope longest, and will therefore be thehottest. Hence, the hotter coolant leaving the system is precisely thecoolant that should be leaving, while the cooler coolant cannot exit thesystem until it has travelled through the entire system and thus becomehotter and therefore ready to leave.

While the disclosure thus far has discussed the preferred embodiment, itwill be obvious to someone of ordinary skill that there are manyalternative embodiments for achieving the result of the disclosedinvention. For example, although a liner, stick configuration and asingle explosive device was discussed here, any other geometricconfiguration of explosives, including a plurality of explosive devices,and/or including the introduction of various delay timing features asamong such a plurality of explosive devices, is also contemplated withinthe scope of this disclosure and its associated claims. This wouldinclude, for example, the various explosive configurations such as thosedisclosed in the various U.S. Patents earlier-cited herein, whereinthese explosive configurations are provided a similar means by which acoolant can be delivered to the explosive in such a way as to permiton-line detonation. In short, it is contemplated that the delivery ofcoolant to one or more explosive devices by any means obvious to someoneof ordinary skill, enabling those explosive devices to be introducedinto an on-line fuel-burning facility and then simultaneously orserially detonated in a controlled manner, is contemplated by thisdisclosure and covered within the scope of its associated claims.

Further, while only certain preferred features of the invention havebeen illustrated and described. many modifications, changes andsubstitutions will occur to those skilled in the art. It is, therefore,to be understood that the appended claims are intended to cover all suchmodifications and changes as fall within the true spirit of theinvention.

We claim:
 1. An explosives-based system for deslagging a hot, heat-exchange device (31), comprising: an explosive device (101); a cooling envelope (104, 104′) enveloping said explosive device (101); coolant-delivery means (12, 106) delivering a flow of coolant into said cooling envelope (104, 104′) such that said explosive device (101) is thereby surrounded and cooled by said coolant; explosive positioning means (12, 106, 112) for holding and moving a first of two ends of said explosive positioning means (12, 106, 112), and thereby moving the cooled explosive (101) affixed proximate a second of said two ends of said explosive positioning means (12, 106, 112) into and within said hot, heat exchange device (31) into a proper position for deslagging the heat exchange device (31) by detonation of said explosive device (101), while said coolant is so-delivered into the envelope (104, 104′) and thereby prevents the heat of said heat exchange device (31) from detonating said explosive device (101), and while said at least one person remains outside said hot, heat exchange device (31); and detonating means for detonating said explosive device (101) at will; wherein: said cooling envelope (104, 104′) is semipermeable (105); whereby: coolant entering the envelope (104, 104′) through a coolant entry opening of the envelope (104, 104′) exits the envelope (104, 104′) through the permeations (105) in the envelope (104, 104′), resulting in a steady flow of coolant to and past said-explosive device (101), out of said envelope (104, 104′) without return flow, prior to and during its introduction into said heat exchange device (31), and prior to and when said explosive device (101) is so-detonated.
 2. The system of claim 1, wherein said coolant-delivery means (12, 106) and said explosive positioning means (12, 106, 112) coincide such that said coolant is so-delivered to said cooling envelope (104, 104′) through said explosive positioning means (12, 106, 112).
 3. The system of claim 1, wherein said cooling envelope (104, 104′) is semipermeable (105) in the region surrounding the explosive (101) and impermeable in the region proximate said coolant entry opening; whereby relatively hotter coolant which has been in the envelope (104, 104′) for a relatively time exits the envelope (104, 104′) before relatively cooler coolant which has been in the envelope (104, 104′) for a relatively shorter time, resulting in more effective cooling of the explosive (101).
 4. The system of claim 1, wherein said cooling envelope (104, 104′) is wider in the region surrounding the explosive (101) and narrower in all other regions; whereby the explosive (101) is properly cooled while the weight of coolant within the envelope (104, 104′) is maintained as low as possible, therefore making it easier to properly position the explosive (101) for deslagging detonation.
 5. The system of claim 1, wherein said coolant-delivery means (12, 106) comprises a coolant delivery pipe (106) coincident with said second end, and is connected at said second end to and within said cooling envelope (104, 104′) such that a section of said coolant delivery pipe (106) resides outside said cooling envelope (104, 104′) and a remaining section of said pipe (106) resides within said cooling envelope (104, 104′), and wherein the coolant flow into the envelope (104, 104′) is realized by said coolant entering the section of the pipe (106) residing outside the envelope (104, 104′), flowing through the pipe (106) to said remaining section within the envelope (104, 104′), and then exiting said remaining section into the envelope (104, 104′).
 6. The system of claim 1, further comprising explosive connector means (112) connecting said explosive device (101) in a position within said cooling envelope (104, 104′), wherein said coolant-delivery means (12, 106) further comprises a coolant delivery pipe (106) coincident with its second end, wherein said explosive connector means (112) is affixed to the explosive (101) and the pipe (106) so as to maintain the explosive (101) and the pipe (106) in position relative to one another, and hence the explosive (101) in said position within said cooling envelope (104, 104′).
 7. The system of claim 1, further comprising explosive connector means (112) connecting said explosive device (101) in a position within said cooling envelope (104, 104′).
 8. The system of claim 1, further comprising a cap (102) affixed to the explosive (101), and an initiator (103), wherein activation of said initiator (103) activates said cap (102), and the activation of said cap (102) in turn detonates the explosive (101).
 9. The system of claim 8, wherein the cap (102) is so-activated by the initiator (103) via a remote control, wireless signal (401).
 10. The system of claim 1, said coolant-delivery means (12, 106) comprising a hydraulic tube (122) attached to a separate coolant delivery pipe (106), wherein each of said explosive device (101), said cooling envelope (104, 104′), said coolant delivery pipe (106), explosive connector means (112) connecting said explosive device (101) in a position within said cooling envelope (104, 104′), and said hydraulic tube (122) is a separate module of said system prior to the assembly of these modules into said system, and wherein subsequent to said assembly, the resulting configuration is such that: a cap (102) is affixed to the explosive (101); a signal connection is established between an initiator (103) and said cap (102); the pipe (106) and the explosive (101) are affixed in position relative to one another, via said explosive connector means (112); the envelope (104, 104′) is affixed to a first of two ends of the pipe (106) such that it envelopes the explosive (101); and the hydraulic tube (122) is affixed to a second of said two ends of the pipe (106).
 11. A method for deslagging a hot, heat-exchange device (31), comprising the steps of: delivering a flow of coolant into a cooling envelope (104, 104′) enveloping an explosive device (101), via coolant-delivery means (12, 106), such that said explosive device (101) is thereby surrounded and cooled by said coolant; holding and moving a first of two ends of an explosive positioning means (12, 106, 112), and thereby moving the cooled explosive (101) affixed proximate a second of said two ends of said explosive positioning means (12, 106, 112) into and within said hot, heat exchange device (31) into a proper position for deslagging the heat exchange device (31) by detonation of said explosive device (101), while so-delivering said coolant into the envelope (104, 104′) and thereby preventing the heat of said heat exchange device (31) from detonating said explosive (101), and while remaining outside said hot, heat exchange device (31); and detonating said explosive device (101) at will, once said cooled explosive (101) has been moved into said proper position for deslagging detonation; wherein said cooling envelope (104, 104′) is semipermeable (105); and whereby: the step of delivering the coolant flow thereby further comprises enabling said coolant to enter the envelope (104, 104′) through a coolant entry opening of the envelope (104, 104′) and exit the envelope (104, 104′) through the permeations (105) in said envelope (104, 104′), resulting in a steady flow of coolant to and past said explosive device (101), out of said envelope (104, 104′) without return flow, prior to and during its introduction into said heat exchange device (31), and prior to and when said explosive device (101) is so-detonated.
 12. The method of claim 11, wherein the step of delivering a flow of coolant into said cooling envelope (104, 104′) comprises delivering said coolant to said cooling envelope (104, 104′) through said explosive positioning means (12, 106, 112).
 13. The method of claim 11, wherein said cooling envelope (104, 104′) is semipermeable (105) in the region surrounding the explosive (101) and impermeable in the region proximate said coolant entry opening; whereby relatively hotter coolant which has been in the envelope (104, 104′) for a relatively longer time will exit the envelope (104, 104′) before relatively cooler coolant which has been in the envelope (104, 104′) for a relatively shorter time, thereby enhancing the step of delivering the coolant flow.
 14. The method of claim 11, wherein said cooling envelope (104, 104′) is wider in the region surrounding the explosive (101) and narrower in all other regions; whereby the explosive (101) is properly cooled while the weight of coolant within the envelope (104, 104′) is maintained as low as possible, thereby making easier the step of holding and moving said coolant-delivery means (12, 106) in a manner that enables proper positioning of the explosive (101) for deslagging.
 15. The method of claim 11, wherein said coolant-delivery means (12, 106) further comprises a coolant delivery pipe (106) coincident with its second end, and is connected at said second end to and within said cooling envelope (104, 104′), and wherein the step of delivering the coolant flow into the envelope (104, 104′) further comprises said coolant entering said coolant delivery pipe (106) from a section of the pipe (106) residing outside the envelope (104, 104′), flowing through the pipe (106) to a remaining section within said cooling envelope (104, 104′), and then exiting said remaining section into the envelope (104, 104′).
 16. The method of claim 11, wherein said explosive device (101) is connected via explosive connector means (112) in a position within said cooling envelope (104, 104′).
 17. The method of claim 11, wherein a cap (102) is affixed to the explosive (101), and wherein the step of detonating said explosive device (101) at will comprises the steps of activating an initiator (103), said initiator (103) in turn activating said cap (102), and said cap (102) in turn detonating the explosive (101).
 18. The method of claim 17, wherein the step of said initiator (103) activating said cap (102) comprises sending a remote control, wireless signal (401) from said initiator (103) to said cap (102). 